Vitamin C has a reputation as the go-to vitamin for overall health—and for good reason, considering how many important functions in the body it has. The powerful antioxidant helps our body absorb iron, produce collagen, promote wound-healing, and keep our immune system healthy, according to New York City-based dietitian Keri Gans, R.D.N., C.D.N.

So, given all of its benefits, you’d think you’d want to load up on all the C, right? Not necessarily. Though many supplements pack large doses of C, taking a ton at once may actually do more harm than good.

If you want your vitamin C supplement to truly be effective, keep the following pointers in mind.

Issues with Going Overboard on vitamin C

The biggest issue with taking a huge dose of vitamin C at once is that it won’t be 100-percent absorbed by the body.

“Vitamin C is a water-soluble vitamin, so the body essentially takes what it needs and excretes what it doesn’t,” says dietitian Amber Pankonin, R.D., L.M.N.T., creator of the food blog Stirlist.

In fact, research suggests that only doses of C under 200 milligrams are completely absorbed. So if you’re taking more than 1,000 milligrams at once, you can expect only about 50 percent of that vitamin C to be absorbed, says Jonathan Valdez, R.D.N., dietitian for Genki Nutrition and spokesperson for New York State Academy of Nutrition and Dietetics.

Read More: Are You Unconsciously Hurting Your Immune Health?

Not to mention, going way too hard on vitamin C can also upset your system. “The upper limit (UL) is 2,000 milligrams, which means that if you take a dose greater than, you may experience gastrointestinal discomfort,” Valdez says. Since your digestive system can’t absorb or tolerate such excessive amounts, taking this much can cause diarrhea, nausea, vomiting, and abdominal cramps.

In the long run, it can also contribute to kidney issues, adds Valdez. In fact, experts suggest that excess C can potentially raise your risk of developing kidney stones. So, if you have a history of kidney stones, consult your physician before supplementing with C.

what IS the most vitamin C you should take in a Day? 

According to the USDA Dietary Guidelines, the RDA (recommended daily allowance) for vitamin C is 75 milligrams for women and 90 milligrams for men. However, you can safely get more than that per day. (Again, the upper limit is 2,000 milligrams.)

“You can consume a larger amount, and what your body doesn’t need, it will excrete out in your urine,” says Gans

If you’re going to supplement, Gans recommends sticking to doses of 200 milligrams every three hours or so to promote truly optimal absorption. Try Garden of Life mykind organics Vitamin C Spray, which provides 60 milligrams per serving. If you do decide to take larger doses, opt for a time-release formula, like Solaray Time-Release Vitamin C (500 milligrams).

How To Properly Ramp Up Your C Through Diet

If you prefer to level up your intake of the antioxidant through your diet, you can do so in a way that maximizes absorption pretty easily.

Read More: 10 Sources Of Vitamin C That Aren’t Oranges

“For example, if you had a cup of orange juice (124 milligrams) at breakfast, a cup of strawberries (108 milligrams) with lunch, a cup of raw red and green peppers with hummus (155 milligrams) as an afternoon snack, a cup of cooked broccoli (114 milligrams) at dinner, and a cup of pineapple (79 milligrams) for dessert, you’ll have consumed almost 600 milligrams,” says Gans.